[JAVA] 대소문자 바꿔서 출력하기

영어 알파벳으로 이루어진 문자열 str이 주어집니다. 각 알파벳을 대문자는 소문자로 소문자는 대문자로 변환해서 출력하는 코드를 작성해 보세요.

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풀이1)

import java.util.Scanner;

public class Solution {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.nextLine();
        String result = "";
        for(int i=0;i<a.length();i++){
            int c = (int) a.charAt(i);
            //대문자일때
            if(c>=65 && c<=90){
                result+=""+(char)(a.charAt(i)+32);
            } //소문자일때
            else if(c>=97 && c<=122){
                result+=""+(char)(a.charAt(i)-32);
            }
        }
        System.out.println(result);
    }
}

풀이2) toUpperCase() toLowerCase()

import java.util.*;

public class Solution {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        String answer = "";

        //Stack <Character> stack = new Stack <> ();

        for(Character c : a.toCharArray()){
            if(Character.isUpperCase(c)){
                //stack.push(Character.toLowerCase(c));
                answer += Character.toLowerCase(c);
            }
            else if(Character.isLowerCase(c)){
                //stack.push(Character.toUpperCase(c));
                answer += Character.toUpperCase(c);
            }
        } 
        System.out.println(answer);
    }
}